Pluck arrived at the school parking lot at 6:16 a.m. and changed parking spots once a few minutes after arriving. An employee of the school saw the car around 9:20 a.m., but no one else checked the vehicle until late afternoon.

Police did not find any medication, weapons or other substances in the car that could have been used to cause a death.

It could take several weeks for autopsy and toxicology reports to be finished, according to the police report.

Investigators are looking into three possible scenarios:

— Murder-suicide: Pluck caused the death of her children and then killed herself.

— Suicide and accidental death: Pluck committed suicide and the children died from accidental causes, such as heat buildup in the car.

— Accidental death: All three died of an accidental cause, such as the heat buildup in the car.

The Department of Social Services and the Embassy of Guyana have been working to coordinate the return of Allison Pluck to her family in Guyana. The father of the two children has made arrangements to have them buried in the United States.